Hydrodynamic thrust bearings are in wide use in high speed rotating machinery because of their long, trouble free life. Gas thrust bearings have the additional advantages of very low power losses and extreme high temperature capability. In addition, the advantage of eliminating the oil supply, scavenging, cooling, filtering and pressurizing equipment necessary to serve oil bearings makes the air bearing extremely desirable.
Because of these desirable characteristics of gas thrust bearings, they are being considered for applications in which their present capabilities can be exceeded. These applications primarily involve greater loading conditions in which the load carrying capacity of the gas film is exceeded. They also involve rotor unbalance and misalignment conditions wherein the thrust runner is not perfectly parallel to the thrust plate, and also extreme heating conditions wherein the thermal distortion of the bearing members or the rotor causes the thrust runner to carry a disproportionate amount of its load on its inner edge.
The most serious limitation on gas thrust bearings in the past has been their load carrying capacity. Compared to conventional thrust bearings such as ball bearings and the like, the load carrying capacity of conventional gas thrust bearings is relatively low. This limitation has always been regarded as more than offset by the other advantages offered by the gas thrust bearing. However, it would be desirable to increase the load carrying capacity. One way of increasing the load carrying capacity is by increasing the size of the bearing surface, but this expedient may be precluded by the size limitations of the machine in which the bearing is going to be located, and has the disadvantage that the power loss in a thrust bearing increases as the fourth power of the bearing diameter.
Accordingly, it would be extremely advantageous to be able to increase the load capacity of a gas thrust bearing without increasing the bearing diameter.